Static digital data entry method and apparatus for a timer or clock

ABSTRACT

A data system and method for entering, storing and displaying a desired digital time which replaces a conventional input keyboard, rotary switch, or thumbwheel switch for a digital timer or clock. This system processes the voltage from a manually positioned wiper of a potentiometer through an inexpensive analog-to-digital converter, displays the digital data to the operator for identification, and holds the data for further processing. The operator repositions the wiper so as to sequentially display a digital time in response to a static or steady state digital signal until the desired digital time is displayed.

This is a continuation, of application Ser. No. 763,399, filed Jan. 28,1977, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a method and apparatus for entering digitaldata into a display timer or clock.

In the past, the most prevalent device for transferring data from anoperator into a data processing system has been a keyboard. Although thekeyboard is universally used for entering data, rotary switches withdiscrete positions and thumbwheel switches with discrete positions havealso been used in certain specific applications. However, all of thesedevices inherently require relatively expensive hardware. This drawbackis especially disadvantageous in a highly competitive market such as thehousehold appliance market.

Another type of device which is relatively inexpensive but inconvenientto use is an operator controlled oscillator which cycles a systemthrough each of the digital states allowed by the system until thedesired digital number appears on the display. This type of input ismost commonly used to set the time on digital clocks. However thisdevice is not well suited for other data entry applications whereessentially random data is to be entered due to the inconvenience ofcycling through all of the possible states and then stopping exactly onthe desired state.

Therefore, it can be appreciated that a data entry device and methodwhich is both inexpensive and convenient to use is highly desirable.

Accordingly, an object of this invention is to provide an inexpensiveapparatus and method to enter data into a digital timer or clock.

It is another object of this invention to provide a data entry apparatusand method which utilizes an analog-to-digital converter which has aconversion error in excess of the maximum data entry system error.

Yet another object of this invention is to provide a digital entrysystem which holds the input time while the initial time is beingprocessed so that the original time can be reentered again withoutoperator adjustment.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a digital data entry method forvisually displaying an operator desired digital time which processes avoltage from a manually positioned wiper of a potentiometer through aninexpensive analog-to-digital converter, and displays the digital datato an operator for identification. The operator then repositions thewiper so as to sequentially display digital time in response to staticor steady state digital signals until the desired digital time isdisplayed.

The present invention also relates to a digital data entry apparatus forvisually displaying an operator desired digital time which comprises ameans for producing an analog voltage in response to a mechanicalposition. A converter quantitizes the analog voltage into a steady statediscrete level. Means for displaying a digital representation of thesteady state discrete level allows an operator to identify the steadystate discrete level and to adjust the mechanical position until thedigital representation corresponds to the operator desired digital time.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 depicts the block diagram logical schematic of the invention inone embodiment; and

FIG. 2 is a block electrical diagram of the invention in a secondembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring to FIG. 1, a variable operator input 10 comprises apotentiometer 12 which is manually adjusted by an operator. In order toconvert the analog voltage appearing on the wiper 14 of thepotentiometer 12 into a form suitable for binary storage and counting asperformed by four presettable counters 16, ananalog-to-binary-coded-decimal converter 18 translates the voltage atthe wiper 14 into a 4 bit digital number which is impressed oninterconnecting lines 20 and thereby into the four presettable counters16. A second set of operator controlled inputs comprising enableswitches 22, 24, 26 and 28, connected to the presettable counters 16,provide means for individually addressing each of the four counters andenabling their contents to be responsive to the variable operator entry10. Connecting lines 30 couple the outputs from each of the fourpresettable counters 16 into the decoder drivers 32 which in turn drivethe output four digit display 34 via interconnect lines 35. The display34 provides a visible decimal representation of the state of thepresettable counters 16 to the operator. Also coupled to the outputlines 30 is digital data processing circuitry 36 which in turn providesa clock pulse on line 38 back to the presettable counters 16. Thedigital processing circuitry 36 is any one of various types well knownto those skilled in the art. A third operator input consists of a modeswitch 40 whereby the operator either inhibits the count down of thepresettable counters 16 and the digital processing circuitry 36 andenters data into the counters via the potentiometer 12, or enables theprocessing circuitry and the presettable counters during which time thecounters are responsive to the clock input line 38.

For purposes of illustrating the function of the present invention, itwill be assumed for example that operator wishes to operate a heatingprocess for 18 minutes and 54 seconds. The operator first places themode control switch 40 into the enter data position 42 thereby disablingthe clock inputs conducted by line 38 to the presettable counters 16 andinhibiting the digital processing circuitry 36. Next, the operatoractuates enable switch 22 corresponding to the left most digit andobserves the display 34 while rotating the manual entry potentiometer 12until the number 1 appears in the left-most digit. In a similar manner,the operator actuates enable switches 24, 26 and 28 while observing thecorresponding display digit and adjusting the potentiometer until thedisplay reads 1, 8, 5, 4. At this time, the presettable counters 16 arepreset to the number shown on the display 34, that is 18 minutes and 54seconds, and this information is transferred via the output lines 30 tothe digital processing circuitry 36. The operator then switches the modecontrol switch 40 to the operate position 44 which enables the digitalprocessing circuitry 38 to begin the timed heating process, and causesthe presettable counters 16 to start counting down from 18 minutes and54 seconds in response to the clock pulse on line 38. The digitalprocessing circuitry 36 continually monitors the state of the counterswhile controlling the heating process. When the digital processingcircuitry 36 senses that the proper time has passed, that is thepresettable counters 16 have counted down to zero, then the heater willbe shut off.

The embodiment of FIG. 1 has the advantage of permitting the use of aninexpensive potentiometer and an inexpensiveanalog-to-binary-coded-decimal converter since the accuracy of-the-A toBCD converter is not important. The accuracy of the potentiometer 12 andthe analog-to-binary-coded-decimal converter 18 is not important in thisapplication since the digital equivalent of the output of theanalog-to-binary-coded-decimal converter 18 is displayed back to theoperator via the display 34 for verification and adjustment of thepotentiometer 12 if necessary. Thus, the resultant data entry error ismuch less than the conversion error of the A-to-D converter. Also, thisis a static data entry system since each potentiometer positioncorresponds to a single digit on the display, which results in aconvenient and simple data entry system.

The second embodiment of the invention, shown in FIG. 2, is very similarto the embodiment of FIG. 1. A variable operator input means 46 producesan analog voltage at line 48 which is digitized by ananalog-to-binary-coded-decimal converter 50 and transferred to fourpresettable counters 52. Although the potentiometer 12 of FIG. 1 hasbeen replaced by four potentiometers, 54, 56, 58, and 60 in FIG. 2, theanalog-to-binary-coded-decimal decoder 50, the four presettable counters52, the mode switch 62, the decoder drivers 64, the display 66 and thedigital processing circuitry 68 and their corresponding interconnectionsare all identical to the corresponding blocks and connections of FIG. 1.Added to the circuit of FIG. 1 is a multiplexor 70 which selects one ofthe four potentiometers 54, 56, 58 or 60 and at the same time enablesone of the four presettable counters of block 52 to be responsive to theoutput of the analog-to-binary-coded-decimal converter 50. Themultiplexor 70 applies a DC voltage to each of the four potentiometers,54, 56, 58 and 60 in turn, thereby coupling the analog voltageequivalent of the potentiometer wiper position through the isolatingdiodes 80 into the analog-to-binary-coded-decimal converter 50 to beencoded into digital signals. These digital signals are fed into thecorresponding presettable counter selected by the multiplexor. Asbefore, each of the four presettable counter outputs is coupled into thedecoder driver 64 which converts the digital signals into the propersignals to drive the display 66.

The operator, in using the embodiment of FIG. 2, would first set themode switch 62 into the enter data position 72. With mode switch 62 inthis position, the digital processing circuitry 68 is inhibited, theclock input 74 to the presettable counter 52 is inhibited, and each ofthe counters are being enabled in turn by the multiplexer 70 to receivethe digital data from the analog-to-binary-coded-decimal converter 50.Since the multiplexor is rapidly sampling each potentiometer 54, 56, 58,and 60 and simultaneously enabling each of the preset inputs to thepresettable counters 52, it appears to the operator that the position ofeach potentiometer is continuously digitally encoded, stored in thepresettable counters, and indicated on the display 66. The operatortherefore observes the display and adjusts the potentiometers until thedisplay indicates the desired time period. At that point the presettablecounters are holding the digital time shown on the displays. Placing themode control switch 62 in the operate position 76 allows the digitalprocess circuitry to begin its process and allows the presettablecounters 52 to down count via the clock input 74. When the digitalprocessing circuitry 36 senses that the proper time has passed, that isthe presettable counters 16 have counted down to zero, then the processwill be terminated.

This embodiment has the added advantage over the embodiment depicted inFIG. 1 in that the four potentiometer inputs allow the user to re-enterthe same time used in the prior operation without having to re-adjustthe input potentiometers.

While the invention has been particularly shown and described asreference preferred embodiment thereof, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.

What is claimed is:
 1. A digital data entry method for visuallydisplaying a digital representation of an operator desired number whichcomprises:(a) positioning manually and approximately a first mechanicalmember for converting a mechanical position into a steady stateelectrical analog signal having a first magnitude; (b) converting saidsteady state electrical analog signal to a binary coded representationhaving a second magnitude, said second magnitude being in apredetermined relationship with said first magnitude; (c) displayingdigitally a first representation of said binary coded representation tothe operator for identification; and (d) repositioning said mechanicalmember and repeating steps (b) and (c) until said digital representationcorresponds to the operator desired number.
 2. A digital data entrymethod for visually displaying a digital representation of an operatordesired number as in claim 1 further comprising:(a) the additional stepof storing said binary coded representation in a first storage means forsubsequent use by data processing circuitry.
 3. A digital data entrymethod for visually displaying a digital representation of an operatordesired number as in claim 2 further comprising:(a) repeating steps (a)through (d) of claim 9 for a second, third, and fourth reiteration toenter an operator desired number which is divided into a first, second,third and fourth distinct digital representation; and (b) storing saidbinary coded representation for said second, third and fourth distinctdigital representation in a corresponding second, third, and fourthstorage means for subsequent use by data processing circuitry.
 4. Adigital data entry method for visually displaying a digitalrepresentation of an operator desired number as in claim 2 furthercomprising:(a) repeating steps (a) through (d) of claim 9 for second,third and fourth mechanical members in addition to said first mechanicalmember; and (b) storing said binary coded representation representativeof a mechanical position of said second, third, and fourth mechanicalmember in a corresponding second, third, and fourth storage means forsubsequent use by data processing circuitry.
 5. A digital data entrymethod as set forth in claim 1 wherein the operator desired number is anoperator desired time.
 6. A digital data entry system for visuallydisplaying a digital representation of an operator desired numbercomprising:(a) means responsive to at least a first mechanical positionfor converting said first mechanical position to a steady stateelectrical analog voltage having a first magnitude; (b) conversion meansfor converting said steady state electrical analog voltage to a binarycoded representation having a second magnitude, said second magnitudebeing in a predetermined relationship with said first magnitude; and (c)means for displaying a digital representation of said binary codedrepresentation for identification by an operator and for subsequentadjustment by said operator of said first mechanical position to providea subsequent steady state analog voltage until said digitalrepresentation corresponds to the operator desired number.
 7. A digitaldata entry system for visually displaying a digital representation of anoperator desired number as in claim 6 further including:(a) meanscoupled to said conversion means for storing said binary codedrepresentation for use by data processing circuitry.
 8. A digital dataentry system for visually displaying a digital representation of anoperator desired number as in claim 6 further including:(a) meanscoupled to said conversion means for storing a first, second, third, andfourth binary coded representation for use by data processing circuitry.9. A digital data entry system for visually displaying a digitalrepresentation of an operator desired number as in claim 8 wherein saidmeans responsive to at least a first mechanical position is responsiveto a first, second, third and fourth mechanical position and furthercomprises:(a) means for directing said electrical analog voltage fromsaid first, second, third, and fourth mechanical positions into saidmeans for storing a first, second, third, and fourth binary codedrepresentation respectively; and (b) means for displaying a digitalrepresentation of said binary coded representation for identification byan operator and for subsequent adjustment by said operator of saidsecond, third, and fourth mechanical positions until said digitalrepresentations of said first, second, third, and fourth mechanicalpositions correspond to the operator desired number.
 10. A digital entrysystem as set forth in claim 6 wherein the operator desired number is anoperator desired time.
 11. A digital entry system as set forth in claim6 wherein said conversion means has a conversion error in excess of thedata entry error of the digital entry system.